The present invention relates to a method and to an apparatus to carry out hot-chemical processes, in particular a melting and/or a melting-reduction of mixtures comprising foundry dusts, ores and other melting and/or melt-reducible materials, such as, e.g. SiO.sub.2, MgO, TiO.sub.2, Ta.sub.2 O.sub.5 or the corresponding metals, at working temperatures which exceed the melting temperature of highly refractory linings.
It is not possible, using processes presently available, to carry out hot-chemical processes in temperature ranges which exceed the melting temperature of known highly refractory linings. Moreover, presently available melting and melting-reduction processes have a high energy requirement and result in substantial environmental impairment as a result of the discharge of dust contained in the waste gases, unless expensive additional installations are provided. Smelting of foundry dusts, which takes place In large quantities, also encounters considerable difficulties.
East German Patent No. 5-215 803, discloses an attempt to obtain a rapid melting-down and fast reaction between charging-stock component in s shaft furnace with a supply of electrical energy. A plasma jet is formed between a plasma torch, which is arranged centrally and which penetrates through the upper covering of the shaft furnace, and a counterelectrode, which penetrates through the floor of the shaft furnace. The charging stock is charged concentrically about the plasma jet, forming a protective dam comprising solid charging-stock components piling up on the inner wall of the furnace and the charging stock arrives in the region of the plasma jet from the inner side of the protective dam.
This procedure does not, however, permit controlled guiding of the plasma jet for the melting and/or chemical reaction of the dam formed. A continuous operation of a shaft furnace of this kind is not realizable. The waste gases resulting from the reaction must be carried away by the blast-furnace burden, thus causing further disadvantages in connection with this procedure, for instance, the condensation of waste-gas components.